Add section "minimum-stability-per-package"

[cpieroni-macron]

The Satis.json schema has a "minimum-stability-per-package" field:
https://github.com/composer/satis/blob/main/res/satis-schema.json

This is useful for specifying a different minimum stability only for a target package.

This field is not implemented in the Satisfy GUI and is obviously deleted in the satis.json when the configuration is submitted.
Could you add this feature?

Thank you